Pneumatic evacuating device for compressors



A. AUGUSTlN-NORMAND.

PNEUMATIC EVACUATING DEVICE FOR COMPRESSOBS.

APPLICATION F lLED APR.13, 1920. r

Patented Jan. 3, 1922,

Inventar.

its era as r-a renr orrice.

rnc AUGUSTIN-NORMAND, or LE HAVRE, rnancn, ASSIGNOR T CHANTIERS nu: nrnmnns anen'srrn-nonmmn, or LE HAVRE, FRANCE, a CORPORATION or rnencn.

PNEUMATIC EVACUATING DEVICE FOR COMPRESSOBS.

Patented. Jan. 3,1922.

'Application filed April 13, 1920. Serial No. 373,588.

To all whom it may concern:

Be it known that I, Aneos'rm AUeUsriN- NORMAND, engineer, citizen of the French Republic, residing at Le Havre, Department of Seine-lnfrieure, in France, and having P. Qaddress 67 Rue du Perrey, in the said city, have invented certain newand useful Improvements in Pneumatic Evacuating Devices for Compressors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the'same.

This invention relates to an automatic evacuating device for air compressors and other apparatus for the purpose of avoiding the explosions which are often produced at starting and stopping, when the pressure in the compression chambers of said compressor becomes higher than the operating. pressure and a high temperature is produced in such apparatus.

The object of the present'i-nvention'is to provide the compressor with" special blowoff valves and controlling means therefor, said valves opening outwardly and acting "automatically each time the compressor is started Or stopped, and which, in addition, blow 01f each time the pressure becomes too great in the compression chamber, irre spective of the pressure of the air in the an reservoirs, which automatic operation 1 of said device being controlled by the starting and stopping lover of the engine, (not shown), operating the compressor.

At stopping, the back leakage from the air reservoirs and from the higher stages towards the lower stages by reason of valves which do not fit tightly, or past the piston segments, becomes more important and if the run has been of long duration a'certain quantity of the lubricating oil may find its way into the compression chambers of the compressor. As this oil has rarely a sufiiciently high flashpoint, the mixture of its vapour and compressed air whichmay have a'higher ratio than thedesigned ratio can ignite spontaneously duringthe last turns of the machine which precede the stop. At themoment of starting, which follows a stop during which leakages have had time to produce their full effect and during which the high temperature of the walls has volatilized a part of the oily layer which covers them, the same accident may occur. On the other hand, during normal operation it is rare that the combined influences of the disturbing factors above mentioned are suffi ciently accentuated to produce other than partial combustions without a dangerous r se of pressure and of which the effect is simply to foul the delivery valves if there is an excessive supply of lubricant It will be clear therefore that it will be necessary to expel the air charges from all the compression chambers of a compressor at the moment of stopping and during startmg to avoid a dangerous operation.

According to the present invention supplemental cams are mounted on the axle of the lever which operates for example the W eccentric shaft on which are pivoted the needle levers and starting levers of a Diesel engine (not shown) driving a compressor A. Whenthis lever is brought into the position which corresponds to starting and stopping of the engine, one of the said cams comes into action and presses upon a rod which opens a distributing valve for compressed a r in apipe which transmits pressure to all the evacuating valves of the compressor.

The closing rod of each of these valves is then raised by the actlon of compressed am under a d1flierentlal :PIStOIL and evacuation iseifected. p

The accompanying drawing shows in per spective a portion of the engine starting lever and the transmitting apparatus/automatically controlled thereby which in the example shown is pneumatic, and in eleva-v tion a two-stage compressor A furnished with two-evacuating valves B and C.

The startinglever 1 is fixedon a shaft 2 on which is secured in addition .to the engine control, (not shown) a cam 3 called the evacuating cam, this cam having two projections 4 and 5 suitably spaced apart so as to act on the control rod 6' of a valve 7 mounted inside a distributionbox 8. 'The' valve 7 is adapted to connect an inlet pipe 9 for compressed air, which, for example, may be supplied from the starting reservoirs (not shown), through the passage '10 in which the valve 7 is mounted, with a conduit 11 which communicates with a passage 12 in the box 8. i

A valve 13 arranged in the passage 12 is The passage "in can be put into connection with the external air through a port "16,

. Springs suitably arranged constantly maintain the valves on their seats ,when not opposed by the action of the cams on the valve rods. The conduit 11' of the distribution box is prolonged on the otherside of the passage 12 by a port 11. connected by atube 1-7 with the evacuating valves of the com pressor. fl s 7 These valves are constituted by a pointed rod 18 controlling communication between an atmospheric port 20 and a passage 19 connected with the compressor. The. valve, rod 18 is fixed on a little piston 21 subjected to the action of aspring 22 and able to move in a suitable housing or cylinder. A passage 23 opening into the lower part of the cylination and presses on. the rod 6 which opens the-valve 7 of the compressed air distributor and air pressure is thereby transmitted to all the evacuating valves of thecompressor. Therod18 of each of these valves is raised by the action or the compressed air under the dilferential'piston andevacuation is er: fectedr Y At the position Stop evacuationceases. When the lever ismoved below this posit10n evacuation- 1S resumed and contlnues when the lever is in the lower position marked An' when the engine is started.

It only ceases when the lever is raised and attains the j position of normal operation marked Petrol. At this moment the cam 15 operates the valve 13 for emptying the piping locatedbetween the distribution box and the evacuating valve. The cylinders of all the evacuating valves are thereupon connected to the atmosphere and the com' pressor can at once begin. to operate.-

The position or the lever, shown in the figure is that of starting on compressed air. It will be seen that the projection 4 of the cam. 3 presses on rod 6 and holds the valve 7 open whereupon the passage of air in the direction ofjthe arrows raises all the pistons 21 and evacuates the compressors by the ports 20. V

At the Stop position therod 6 will be in the hollow between the two projections 1 and 5 and-closes the communication between pipe 9 and pipe 17. The object of this is to prevent the pistons 21 which are not statically packed from being exposed to the pressure of thestarting reservoirs'during the whole period of a stop. r

H At the;Petrol position the other. pro

ject'ion 5 of the cam 3 passes the rod 6 which jectionoi 'thecam 15' presses on the rod 14 and operates the valve '13 so that the pipe 17 will be connected to the atmosphere by the port 16 whilst the valve 7 forms a stop valve 'for the pipe 9. p It is clear that, various other means of transmission could be employed, mechanlcalc hydraulic, or electrical, for example. 7

The arrangements can also be adapted to any other motor controlgwhether this be .is free to rise, on the other hand, the prochambers in the first place by piping which permits-losses of charge and in the second place by delivery valves which mayrby reason of mechanical damage remain wedged in theclosed position and so interrupt all communication. i

It is to be understood that the'compressed air admitted through the'device when. the valve 7 is open by thecams 4 and 5,.has nothing to do with supplying the compressed air for starting or operating the compressor A, but is'only used to lift the members 18 of the evacuating valves B and (3 so that thecompressor may be evacuated through the passages 19 and 20 of each of the valves g B and G, the devices being usedin conjunction with a two stage compressor.

H vi g now particularly described"and ascertained the nature of my saidinvention and 1nv what manner the same is to be performed, l. declare that what I claim is 1. Inan evacuating arrangement for a1r compressors or the like, thecombination with a control lever of evacuating valves associated with said compressor, compressed air supply and exhaust valves for operating theevacuating valves, means for establishing communi'irationbetween said air supply and exhaust valves and evacuating valves and meanscarried by said control lever automatically operating,the air supply and ex-1 haust valves for opening said evacuating valves at the proper time and for the purpose specified] 1 2; In an evacuating arrangement for air compressors or the like, the combination with a control lever ofa shaft for said lever, evacuating valves associated with said compressor, compressed. airsupply and exhaust valves for operating the evacuating valves,

means for. establishing communication b tween-said air supply and exhaust valve and evacuating valves, and cams carried'by the shaft of said control lever for operating the air supply and exhaust valves for opening and ermitting the closing of the evacuating va ves at the proper time and for the purpose specified.

3. Inan evacuating arrangement for air compressors or the like, the combination of a control lever, a shaft for said lever, evacuating valves associated with the compressor,

vcompressed air supply and exhaust valves evacuating spring pressed piston valves associated With the compressor, compressed air supply and exhaust valves for operating the evacuating valves, a pipe for establishing communication between said air supply and exhaust valves and evacuating valves and a pair of cams carried by the shaft of said control lever, one of said cams adapted to operate the compressed air supply valve for opening the evacuating valves, and the other cam adapted to operate the exhaust valve at the desired time for exhausting to the atmosphere the pipes supplying the compressed air to the evacuating valves, permitting the springs to close the evacuating valves.

a control lever, a shaft for said lever,

In testimony whereof I alfix my signature,

in presence of two Witnesses.

A. AUGUSTIN-NORMAND.

Witnesses:

LEWIS V. BOYLE, JOHN CQRRIGAN, JR. 

